Structural basis for reversible photoswitching in Dronpa
Structural basis for reversible photoswitching in Dronpa
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DOI：
10.1073/pnas.0700629104
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发表时间：
2007-08-07
影响因子：
11.1
通讯作者：
Jakobs, Stefan
中科院分区：
文献类型：
--
作者：
Andresen, Martin;Stiel, Andre C.;Jakobs, Stefan
Dronpa 是一种新型 GFP 样荧光蛋白，具有卓越的光控开关特性。它可以通过光照射在荧光开启状态和非荧光关闭状态之间可逆地切换。为了阐明转换机制的分子基础，我们生成了可逆转换的 Dronpa 蛋白晶体。使用这些晶体，我们以 1.95 埃的分辨率确定了卓巴难以捉摸的暗态结构。我们发现光开关导致发色团的顺反异构化，并伴随着四个附近氨基酸残基的复杂结构重排。由于分子内事件的级联，发色团暴露于不同的静电表面电势，这可能会影响发色团的质子化平衡。我们提出了光诱导切换机制的综合模型，将一系列结构重排与发色团的不同质子化状态连接起来。
Dronpa is a novel GFP-like fluorescent protein with exceptional light-controlled switching properties. It may be reversibly switched between a fluorescent on-state and a nonfluorescent off-state by irradiation with light. To elucidate the molecular basis of the switching mechanism, we generated reversibly switchable Dronpa protein crystals. Using these crystals we determined the elusive dark-state structure of Dronpa at 1.95-angstrom resolution. We found that the photoswitching results in a cis-trans isomerization of the chromophore accompanied by complex structural rearrangements of four nearby amino acid residues. Because of this cascade of intramolecular events, the chromophore is exposed to distinct electrostatic surface potentials, which are likely to influence the protonation equilibria at the chromophore. We suggest a comprehensive model for the light-induced switching mechanism, connecting a cascade of structural rearrangements with different protonation states of the chromophore.